Baby Mice Born from Eggs Made from Stem Cells

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Katherine Harmon Courage is a freelance writer and contributing editor for Scientific American. Her book Octopus! The Most Mysterious Creature In the Sea is out now from Penguin/Current. Follow on Twitter @KHCourage.

Stem cells have been coaxed into creating everything from liver cells to beating heart tissue. Recently, these versatile cells were even used to make fertile mouse sperm, suggesting that stem cell technology might eventually be able to play a role in the treatment of human infertility.

Now two types of stem cells have been turned into viable mouse egg cells that were fertilized and eventually yielded healthy baby mice. Details of this achievement were published online October 4 in Science.

Mouse oocytes; image courtesy of Katsuhiko Hayashi

Katsuhiko Hayashi, of Kyoto University’s School of Medicine, were able to create the eggs with embryonic stem cells as well as with induced pluripotent stem cells (formed from adult cells).

The team started with female embryonic stem cells and then coaxed them genetically to revert to an earlier developmental stage (primordial germ cell-like cells). These cells were blended with gonadal somatic cells, important in the development of sexual differentiation, to create “reconstituted ovaries.” The researchers then transplanted these cultured assemblages into female mice (in either the actual ovary or the kidney) for safekeeping and to allow the stem cells to mature into oocytes in a natural environment.

To test the eggs’ fertility, the new oocytes were removed from the mice for an in vitro fertilization with mouse spermand then re-implanted into the female mice. The experimental females went on to bear normally developing and fertile offspring. The procedure was then also performed successfully with induced pluripotent stem cells from adult skin cells with similar results.

“Our system serves as a robust foundation to investigate and further reconstitute female germline development in vitro,” the researchers noted in their paper,” not only in mice, but also in other mammals, including humans.”

About the Author: Katherine Harmon Courage is a freelance writer and contributing editor for Scientific American. Her book Octopus! The Most Mysterious Creature In the Sea is out now from Penguin/Current. Follow on Twitter @KHCourage.

7 Comments

I really liked this blog and it has a connection to my Topic in BioLit Gene Transfer. Because this topic Stem cell technology have cells that have been coaxed into creating things like liver cells to beating heart tissue. Also cells were used to make fertile mouse sperm, suggesting that stem cell technology might eventually be able to play a role in the treatment of human infertility. So this is kind of like Gene transfer from liver cells to making fertile mouse sperm.

If both eggs and sperm were made from stem cells, what genes would they carry?

If humans are born from this technology, will they be told of their origins? What would be the psychological effect of knowing how they were created? It isn’t like the IVF children who are simply helped to exist from normal eggs and sperm.

This is just a guess on my part, but the sentence “These cells were blended with gonadal somatic cells” leads me to believe that the nucleus from the somatic cell was used to replace the nucleus in the egg cell, so it would have the correct number of chromosomes without needing to undergo meiosis.